On 1/30/07, Tom Lane <tgl@sss.pgh.pa.us> wrote: "Pavan Deolasee" <pavan.deolasee@gmail.com> writes:
> The stack usage for toast_insert_or_update() may run into several KBs since
> the MaxHeapAttributeNumber is set to a very large value of 1600. The usage
> could anywhere between 28K to 48K depending on alignment and whether its a
> 32-bit or a 64-bit machine.
So? The routine is not re-entrant so I don't see that the stack space
is a big problem. It's coded that way to avoid palloc/pfree cycles...
I always thought that it would be costlier to have a repeated stack allocation/deallocation
of many KBs than dynamically allocating a small percentage of that. But I might be wrong.
In fact, a small test I ran showed that mallloc/free is more costly. So may be are
good.
Btw, I noticed that the toast_insert_or_update() is re-entrant. toast_save_datum()
calls simple_heap_insert() which somewhere down the line calls
toast_insert_or_update() again. It looks a bit surprising, haven't look into detail
though.
Thanks,
Pavan
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